Improvement in steam-engine valve-gears



c. ROGERS.

Steam-'Engine Valve-Geas. l N0,149,067 Patented March 31,1874.

l MM/M73@ ,j D. r n www dawg/M n m UNITED STATES PATENT OFFICE.

CHARLES ROGERS, OF ALLEGHENY, ASSIGNOR TO JAMES A. HUTOHISON, OF PITTSBURG, PENNSYLVANIA.

IMPROVEMENT IN STEAM-ENGINE VALVE-GEARS.

Specification formirg part of Letters Patent No., 149,067, dated March 3l, 1874; application filed January 29, 1874.

CASE A.

Y vented new and useful Improvements in Steam- Engine Valve-Gear; and I do hereby declare the following to be a full, clear, and exact description thereof, reference being had to the accompanying drawing making a part of this specification, in which- Figure l is aside view of an engine and pump, showing a vertical central section of the steam-cylinder 5 Fig. Y2, a detail section, on an enlarged scale, showing the construction and operation of the auxiliary valve.

My invention relates to the mechanism for operating the slide-valve in direct-acting engines-z' e., engines dispensing with the ilywheel and crank.

To enable others skilled in the art to make and use inyimprovement, I will proceed to describe its construction and mode of operation.

In the drawing, A is the steam-cylinder, B, the piston; B', the piston-rod, which connects with a pumping-piston in the pump O, or connection may be made with any other device or machine for communicatingpower 5 D D, steamports; E, exhaust-port; F, slide-valve, operated 'by the double headed piston G, to which it is secured. This piston ts in the small cylinder H, which forms the upper part of the steam-chest I. The live steam is admitted to both ends of the piston G through the small steam-ports a a, giving a uniform pressure on all sides of the piston, which is, therefore, perfectly balanced. b b are steam-ports, cominunicating from the cylinder H to the auxiliary valve-chambers K K, from which other the end of the valve-stein and trips the valve,

as shown in the drawing, allowing the steam back of the piston G to escape into the exhaustport, thereby destroying the balance of the piston G, which moves forward and shifts the valve, admitting the steam to the front of the piston and opening the exhaust-port 011 the opposite side. The drawing showsthe slidevalve after it has been shifted, and at the instant the piston B has commenced to move back. As soon as the valve L is relieved from contact with the piston B it seats itself by its own weight, closing the port c and restoring t-he balance of the piston G. The operation of both of the valves L L is the same.

It will be seen that the live steam is at all times admitted equally to both ends of the piston G, which is moved by the opening of the valve L, and the escape of the steam into the exhaust-port.

N is a lever, operated by a wrench on the outside of the steam-chest, for handling the valve when starting the engine.

In Fig. 2 the valve-chamber is shown on an enlarged scale, and the position of the valve shown as open, or, when tipped, by full lines, and by dot-ted lines when closed.

I am aware thatthe double-headed piston for operating the slide-valve, in connection with auxiliary valves is not new, but such auxiliary valves have heretofore rested on their sides, their movement being in the same direction as the piston. Such valves, by reason of their construction, do not wear equally and seat themselves, but wear altogether on the lower side, and therefore need constant attention, retitting, and renewing, whilethe Vthrough stuffing-boxes, which valves have to be returned to their seats by the aid of a spring, is liable to this, among other serious disadvantages, viz., that to open the valves it is required to force a rod through the tight stuflingbox against the pressure of a spring suiiciently'stift' or strong to return the rod, and the spring, if only of sufficient strength to .move the rod when it is Working smoothly in the stuffing-boxes, would be too Weak when the movement of the rod Would be impeded by rust, as would naturally occur after short disuse, While, if lthe spring be stronger than Was necessary to overcome the hard friction in the stuffing-box, it would carry the valve so heavily against its seat as in a short time to batter the one or the other and cause leakage.

What I claim as my invention, and desire to secure by Letters Patent of the United States, 1s-

1. The auxiliary valves L L, having stems d d projecting into the steam cylinder' in the path of the piston and at right angles to its motion, whereby the valve shall be canted 

